COMPARISON OF EXPERIMENTAL AND NUMERICAL METHODS OF PATIENT DOSE ESTIMATIONS IN CT USING ANTHROPOMORPHIC MODELS

Area of Science:

• Medical Physics
• Radiological Protection
• Diagnostic Imaging

Background:

• Accurate patient dose estimation is crucial for computed tomography (CT) safety.
• Current methods include thermoluminescence dosemeter (TLD) measurements and Monte Carlo simulation software.
• Software packages like CT-Expo and CTVoxDos offer advanced dose calculation capabilities.

Purpose of the Study:

• To compare organ doses (ODs) and effective doses derived from TLD measurements and two distinct software packages (CT-Expo, CTVoxDos).
• To evaluate the accuracy of different patient dose estimation methods in CT, specifically for upper abdomen protocols.

Main Methods:

• Utilized an anthropomorphic phantom for thermoluminescence dosemeter (TLD) measurements.
• Employed CT-Expo and CTVoxDos software, which incorporates the ICRP Reference Adult Male (ICRP 110) model, for dose calculations.
• Compared organ doses within primary, partially primary, and scatter radiation fields.

Main Results:

• TLD measurements showed significant deviations from CTVoxDos: (19±16)% in the primary field, (14±2)% for partially primary organs, and (34±38)% in the scatter field.
• CT-Expo estimations deviated from CTVoxDos by (16±9)% for primary irradiated organs and (28±31)% for scatter irradiated organs.
• Substantial variability exists between TLD measurements and software-based dose estimations in CT.

Conclusions:

• Thermoluminescence dosemeter (TLD) measurements and Monte Carlo simulations provide comparable but not identical results for CT patient dose estimation.
• Discrepancies highlight the importance of understanding the limitations and specific models used by different dose estimation tools.
• Further research is needed to refine CT dose assessment methodologies for improved patient safety.